1. Field of the Invention
This invention relates to an image printing apparatus and a method of controlling the same. More particularly, this invention relates to an image printing apparatus which reads an image original and prints it by using a printhead of inkjet printing method and a control method applied to this apparatus.
2. Description of the Related Art
A so-called multi-function printer (MFP) having an image reading function in addition to a print function is recently widespread, replacing a so-called single-function printer (SFP) having only a print function.
In addition to the single-function printer's “print function” of printing print data generated by a host apparatus such as a personal computer, the multi-function printer has the following functions: a “direct print function” of printing image data stored in, e.g., a memory card without intervening a host apparatus such as a personal computer, an “image supply (scan) function” of supplying image data generated from a read original to, e.g., a personal computer, and a “copy function” of copying a read image without intervening a host apparatus such as a personal computer.
Of these functions, the copy function is unique to the multi-function printer since the function cannot be implemented by a single function apparatus such as a single-function printer or scanner. The copy function includes various copy modes to meet the needs of users.
The copy modes include, e.g., a “same-size copy” mode to copy an original of the same size (magnification rate: 100%) to a printing paper sheet and a “fixed rate magnification/reduction” mode to copy an original with a specific size (e.g., A4 original) to printing paper sheet of a specific size (e.g., B5 paper). There is also included an “automatic magnification/reduction” mode to automatically detect the size and position of an original, enlarge/reduce the image at an optimum magnification/reduction rate, and copy the image to a available printing paper sheet.
As is disclosed in Japanese Patent Publication Laid-Open No. 2004-297781, a “marginless copy” mode is also available in which an original is copied to a printing paper sheet without margin. The “automatic magnification/reduction” mode and “marginless copy” mode may be combined.
A multi-function printer having a film reading function has a “film copy” mode to copy an image read from a film to a printing paper sheet.
In the marginless copy mode, an image is enlarged at such a magnification rate that the vertical and horizontal sizes of the image original become equal to or larger than the vertical and horizontal sizes of a printing paper sheet, respectively. After the image original is enlarged, the extra portion over the printing paper size is cut off, thereby equalizing the size of the enlarged image to that of the printing paper sheet.
In marginless printing, an extra-printing area is set at each of the top, bottom, left, and right margins of a printing paper sheet, thereby making the printing area larger than the printing paper size, as disclosed in Japanese Patent Publication Laid-Open No. 2003-177898. Hence, even when the printing paper sheet is slightly off the position, a perfectly marginless printing result without margin can be obtained on the printing paper sheet.
FIG. 8 is a view showing the relationship between a printing paper sheet and a printing area.
As shown in FIG. 8, extra-printing areas (TM, BM, LM, and RM) are set at the top, bottom, left, and right margins with respect to a horizontal size (PW) and vertical size (PH) of a printing papery sheet A01. When printing is done in a printing area A02 having a horizontal size (APW) and vertical size (APH) larger than the printing paper sheet size, a perfectly marginless printing result can be obtained on the printing papery sheet A01.
In the above-described prior art, however, when marginless copy to fill the overall printing area with an image is executed by reading the entire original, an image unnecessary for printing is also read. This increases the time required for image reading and image processing and eventually lowers the throughput. Since the size of image data obtained by image reading is also large, the memory capacity necessary for temporarily holding the image data is also large. This leads to an increase of the apparatus production cost.
FIG. 9 is a view showing the relationship between a reading area, an original area, and the original table area of an MFP having a copy function.
Referring to FIG. 9, an original area A03 indicates the size of a read original. An original table area A04 is the area of a table to place an image original in the MFP. A reading area A05 is an area necessary for actual image printing in the MFP.
As is apparent from this relationship, an area corresponding to the original area A03 is read in marginless copy. An area necessary for printing is the smaller reading area A05. If the difference between the original area A03 and the reading area A05 becomes large, unwanted reading and image processing are executed.
IN_SizeX and IN_SizeY in FIG. 9 indicate the horizontal reading size and vertical reading size of the reading area A05. A reading reference position (R0) is set at the upper left corner of the original table area A04. The coordinate origin is set at this position, horizontal and vertical positions are defined, based on the coordinate origin. The coordinate values of the reading start position (RS) of the reading area A05 are (IN_OfsX, IN_OfsY). The horizontal and vertical sizes of the reading original are OH and OV, respectively. Upon reading an original, a CCD sensor or CIS sensor having a reading width corresponding to the width of the original table area A04 in the horizontal direction scans the original in the direction of an arrow A, thereby reading the image of the entire original.
In marginless copy, if the extra-printing areas of the printed image in view of the print medium are not uniform in the vertical or horizontal direction, the center of the original and that of the image on the printing paper sheet do not match. This produces an unnatural impression for the user.